Tone-arm apparatus for talking-machines



A. J. SWING.

TONE ARM APPARATUS FOR TALKING MACHINES.

APPLICATION FILED NOV.15, 1915.

Patented Aug. 17, 1920.

LVN meow W Q) 0 M PATENT orrics.

ALFRED J. SWING, OF CINCINNATI, OHIO.

TONE-ARM APPARATUS FOR TALKliNG-MAOHINES.

Specification of Letters Patent.

Application nled November 15, 1915. Serial No. 61,668.

To all whom it may concern:

Be it known that I, ALFRED J. SWING, a citizen of the United States,residing at 01neinnati, in the county of Hamilton and State of Ohio,have invented certain new and useful Improvements 1n Tone-Arm Apparatus.for Talking-Machines, of which the following is a specification.

My invention relates to improvements in apparatus for recording andreproducing sound. One of its objects is to provide an improvedarrangement and means to support and guide the sound box and stylus withreference to the record both. in cutting or producing the records, andin reproducing the vibrations therefrom. Another object is to providefor guiding the sound box and pivotally supported stylus carrying memberalong a substantially radial path across the face of the disk record,and preserving the same relative, angular or axial position or relationof the stylus carr ing member with reference to the record an the pointof contact of the stylus therewith at the various positions of thestylus on the record. Another object is to provide improved mechanism tosupport and retain the sound box and stylus carrying member in properrelation to the record in its various positions. My invention alsocomprises certain details of form, combination and arrangement, all ofwhich will be fully set forth in the description of the accompanyingdrawings, in which:

Figure l is a plan view of a record and tone arm illustrating oneembodiment of my invention.

Fig. 2 is a side elevation of the same.

The practice heretofore with disk records of both the hill and dale andlateral cut type has been to pivotally mount the tone arm so that itsfree end may travel through the arc of a circle in traversing the faceof the record from a point near the center of the record to thecircumference of the record. During this travel of the tone arm therecording or reproducing mechanism comprising the sound box, the stylus,and the pivotally mounted stylus carryin member do not change theirrelation to the tone arm,

and hence do not travel in a strictly radial direction, but change theirpositions angularly or axially relative to the record and the line oftravel of the spiral record groove relative to the stylus, to the sameextent that the arc of travel of the stylus diverges the hill from atrue radial line across the face of the record from its centeroutwardly.

y improvements are applicable to both and dale and lateral cut types ofrecord, and to both the mechanism employed to cut the records and to themechanism em ployed to reproduce vibrations from the records.

I have discovered that the essential feature in truthfully engravingsound vibratlons upon the record and in reproducing them, therefrom isto support and retain the was upon whichthe stylus lever vibrates orrotates at right angles to a radial line across the record disk, or inother words in a plane parallel to that portion of the spiral recordgroove being traversed by the stylus. As heretofore practised this axisof rotation of the stylus lever has been permitted to diverge to aconsiderable extent in one direction or the other so as, to occupydifferent positions of angularity as the stylus progressed from thecenter toward the periphery of the record, resulting in the point of thestylus vibrating diagonally across the spiral groove instead oftransversely across the spiral groove. Such diagonal vibration of thestylus point tends to produce or reproduce imperfectly the originalsounds, and also to cause the stylus to climb one wall of the groove.

The accompanying drawings illustrate the preferred embodiment of myinvention. As illustrated A represents the record disk which rotatesupon the center 2. The dotted line 8 8 indicates approximately theradial path or line traversed by the point of the stylus. B representsthe major tone arm section, which rotates or swings relative to thestationary hell or megaphone section E upon a stationary center orvertical axis 3. A minor tone arm section C is pivotally connected upona movable or floating center or axis 4 to the major tone arm section. Asound box D is pivotally connected to the free end of the minor tone armsection C upon a horizontal axis 5 at right angles to the axis 4. Thesound box carries a stylus lever 6 pivoted thereto uponan axis 7 whichoccupies an inclined position in a vertical plane at right angles to theradial line 8 s. The axis 7 is also at right angles to the axis 5 onwhich the sound box is mounted upon the section C. A stylus 8 is carriedby the lever 6. The sound box can be adjusted about its axis 5 tooperative or idle position.

Patented Aug. 17, 1920. p

Attached to the section C is a lug 9 which is pivotally connected to oneend of a link 10, which link is in turn pivotally connected at itsopposite end to a post or stationar center 11 so that as the tone armsection travels across the face of the record, the link causes thesection C to move on its axis 4 with reference to section B tocounteract or compensate for the tendency of the section B to shift theaxis 7 into a plane diagonal to the line 8 s. The eifect of the link 10and consequent movement of the section C upon its axis 4 is to cause thestylus point to travel along a substantially radial line from the marginof the record inwardly, and at all points on the record to be in aposition to vibrate transversely to that portion of the spiral groovewith which it is in contact. I am thus enabled to record or reproducevibrations at all parts of the record under like and correct conditions,and to produce and Work from a superior type of record. With the hilland dale type of record also superior and more uniform results areobtainable by retaining the stylus axis unihaving a stylus to engage therecord and pivotally connected to the free end of said tone arm upon asubstantially vertical axis, and a link member substantially )arallel tosaid tone arm pivotally connecte near the fixed end of the tone arm upona fixed axis and pivotally connected at its opposite end to said soundbox, to cause the sound box to move pivotally relative to the tone armin proportion to the movement of the tone arm upon its fixed axis.

2. In a sound recording and reproducing machine having a rotarilymounted disk record, a major tone arm rotatably movable upon a fixedaxis transverse to the face of said disk, a minor tone arm rotatablymounted upon the free end of said major tone arm upon an axissubstantially at right angles to the face of the record, a sound boxhaving a stylus to engage the record rotatably mounted upon-said minortone arm upon ,an axis parallel to the face of the record,

and a link member substantially parallel to said major tone arm andpivotally mounted near the fixed end of the major tone arm upon a fixedaxis and at its opposite end pivotally connected to said minor tone arm,to cause said sound box to move relative to said major tone arm inproportion to the movement of said major tone arm upon its fixed axis.

In testimony whereof I have ailixed my signature in t e presence of twowitnesses.

ALFRED J. SWING.

Witnesses:

C. W. MILES, W. THORNTON Boennr.

